Geometry node : issue? using capture position attribute to set a Mesline starting points

I want to draw curve between 2 vertices of a mesh. For that I try to Use Attribute Capture with Position, and use for set start and end position of a mesh line... but it doesn't work as shown in the images below. Any help welcome.

• something like the diagram below... ![enter image description here](i.stack.imgur.com/6jk3W.png) a related question : how to control the start en end position of a bezier segment? do I have to use instance on point with a bezier segment as instance? Feb 16, 2022 at 12:59

1 Answer

Nodes spawning meshes require constant values - their sockets are circular. What you're connecting, are fields - their sockets are in diamond shape.

If you have some programming skills, passing a field into a circular socket is as correct as passing a function, where a value is expected instead...

I see what you're going for by deleting geometry twice, rather than just once with Compare to 0.5, Epsillon 0.6 or Equal 0 OR Equal 1. This way you have two geometries, each with just a single point - so the nodes could just pass a single value rather than a field (and maybe it will work this way in the future, who knows).

Instead of Capture Attribute, you can use an Attribute Statistic node:

And since it allows you to select stuff, you don't need to delete geometry:

Or You can use Set Position node to set the correct positions after the Mesh Line is spawned. It accepts fields, so you can use Transfer Attribute node in Index mode - and you don't even need to translate indices in your case:

• Thank you very much Markus for your time and the 3 solutions that help me a lot... It's not very obvious to well understand the geom node from documentation. Do you know where I could find more detailed doc about geo node? Cheers Feb 15, 2022 at 19:25
• @NetCob Robin Betts' answers tagged geonodes, or Official Manual also there's many new nodes available in 3.1, e.g. Edge Neighbors Node, there's a Blender Discord Server which has a channel #help-geonodes, and many youtube tutorials. More educational content than you can ever consume 😁 Feb 15, 2022 at 20:13
• Hello again, If you want, can you help for this use case : I want to start with a geometry, for instance like an UV Sphere, and I want to pick randomly couple of its vertice to create bezier segment for each couple... Feb 16, 2022 at 12:58